In recent years, the worldwide continuous population growth together with the changing food supply/demand mapping are causing concerns on the food shortage at a faster pace. Under the circumstances, one of the countermeasures is considered to improve labor saving and operational efficiency and enhance the productivity in agriculture.
Cultivation techniques, equipment and chemical agents have been studied for a very long time for the purpose of improving labor saving and operational efficiency, and chemical agents, among them, are expected to have a growing future demand due to a small investment for use.
Chemical agents used for the purpose of growing a plant, controlling the growth and saving labor in cultivation practice are called plant growth regulators and provide a wide variety of actions such as growth acceleration, germination inhibition, extension inhibition, induction of seedlessness and fall prevention of fruits, and the like. However, those having growth accelerating action are limited to plant hormones such as gibberellin and synthetic cytokinin and their related substances (Non Patent Literatures 1 and 2).
Period, concentration and amount applicable to these plant hormone-based plant growth regulators are limited to narrow ranges since their actions are significantly affected by the variations thereof. When used under wrong application conditions, these regulators not only fail to provide the expected effects but also fail to exhibit healthy growth, and thus they are not commonly used.
Meanwhile, some amino acid-based compounds are reported to promote plant growth, for example, glutamic acid, glycine, proline, and the like. 5-aminolevulinic acid also has actions such as photosynthesis activity enhancement and nitrogen absorption promotion. These amino acid-based compounds have mild actions and hence have wide ranges of period, concentration and amount which can be applied. For this reason, they are expected to be easy-to-use chemical agents and consequently further development is demanded.
Among the amino acid-based compounds, 5-amino-4-hydroxy pentanoic acid and derivatives thereof are known to have been used as the production intermediate for pharmaceutical products (Patent Literatures 1 and 2) but the actions thereof on plants are not known at all.